In general, each of various types of electronic apparatus has a battery. Such an electronic apparatus is driven using power charged in the battery. The battery of the electronic apparatus may be replaced with new one or may be recharged. To this end, the electronic apparatus includes a contact terminal contacting an external charging device. That is, the electronic apparatus is electrically connected to the charging device through the contact terminal. However, as the contract terminal of the electronic apparatus is externally exposed, the contact terminal is contaminated by foreign materials or short-circuited by humidity. In this case, contact failure may occur between the contact terminal and the charging device and thus the battery of the electronic apparatus may not be charged.
In order to solve the above-described problem, a wireless power charging system for wirelessly charging an electronic apparatus has been proposed. The wireless power charging system includes a wireless power transmission apparatus and a wireless power reception apparatus. The wireless power transmission device wirelessly transmits power and the wireless power reception device wirelessly receives power. Here, the electronic apparatus may include the wireless power reception device or may be electrically connected to the wireless power reception device. At this time, the wireless power reception device should be disposed in a predetermined charging region of the wireless power transmission device. In particular, if the wireless power charging system is implemented using a resonance method, the wireless power transmission device needs to be designed to have the same coupling coefficient regardless of the position of the wireless power reception device. Otherwise, since a transmit power amount change range adjusted by the wireless power transmission device increases according to the position of the wireless power reception device, cost required to implement the wireless power charging system may increase and efficiency of the wireless power charging system may deteriorate.